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Re: why select @@session.tx_read_only take long time
Posted by: Rick James
Date: November 02, 2016 11:43AM

Hmmm... Interesting.
Note that multiple connections ran the same query at the same time and it lasted the same length of time (nearly 19s).

What else was going on? Usually when something like this happens, another process is hogging something. Look further in the slowlog; maybe something else ended at essentially the same time.

Another tool for chasing it down: SHOW ENGINE INNODB STATUS; -- but it needs to be run promptly (unless you have a monitoring tool capturing it).

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Re: why select @@session.tx_read_only take long time
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November 02, 2016 11:43AM


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